1. Field of the Invention
This invention relates to a webbing retractor for winding up a webbing for protecting an occupant in an emergency of a vehicle.
2. Description of the Prior Art
In general, a webbing retractor is provided therein with a lock mechanism capable of abruptly preventing webbing windoff rotation of a takeup shaft in an emergency of the vehicle, to thereby reliable restrain the occupant.
There have been such cases that, when the lock mechanism is used in the passive seatbelt system, wherein, in order to meet the action of the occupant entering or leaving the compartment, the webbing is automatically fastened to or unfastened from the occupant in accordance with the opening or closing action of the door, particularly, if the vehicle is tiltingly stopped at a slope or the like after a collision of the vehicle, unfastening of the webbing from the occupant and opening of the door become impossible. Consequently, there has been proposed an unlock mechanism for permitting the occupant to quickly escape from the compartment in an emergency of the vehicle (U.S. patent application Ser. No. 90,402 now U.S. Pat. No. 4,253,622). This unlock mechanism is constructed such that the occupant turns a release lever to unlock the lock mechanism, whereby the occupant makes it possible to wind off the webbing, so that the occupant can unfasten the webbing from himself to leave the vehicle to outside.
However, with this unlock mechanism, it is necessary to manually restore the release lever when the occupant enters the vehicle again, and, when it is failed to do this restoring operation, even if a dangerous situation takes place during running of the vehicle thereafter, the lock mechanism cannot prevent the webbing from being wound off, so that there will be possibilities of that the occupant cannot be secured in safety.